My Monte's OBD socket has only TWO pins in it?!?
#1
My Monte's OBD socket has only TWO pins in it?!?
Well, this is an oddity (at least to me). I knew that 1995 was the last model year before OBD-II came and straightened everything out, so my '95 Monte had something referred to as "OBD 1.5". It has a twelve-pin socket (whereas the OBD-II ones have sixteen, I believe?) ... but until recently I haven't taken a real close look at it. But for a few months now the "AIR BAG" warning light stays on consistently, so I had my shop look into it, and they tell me that the car's OBD socket has only two pins in it -- and nothing they had would connect and communicate with the PCM.
Here's a pic of the little oddball:
The only two pins it has are on the far right.
Wikipedia's article on on-board diagnostics mentions that GM had a wide and inconsistent variety of ALDL (Assembly Line Diagnostic Link) sockets in their cars until 1996. Apparently so!
The things I can't figure out are:
• How is this supposed to work with only two pins? Shouldn't it have at least three?
• Didn't this ever present itself as a problem for the car's previous owners, when they brought it in to their shops for maintenance?
Weird. Just weird.
Here's a pic of the little oddball:
The only two pins it has are on the far right.
Wikipedia's article on on-board diagnostics mentions that GM had a wide and inconsistent variety of ALDL (Assembly Line Diagnostic Link) sockets in their cars until 1996. Apparently so!
The things I can't figure out are:
• How is this supposed to work with only two pins? Shouldn't it have at least three?
• Didn't this ever present itself as a problem for the car's previous owners, when they brought it in to their shops for maintenance?
Weird. Just weird.
#2
Join Date: Apr 2010
Location: Mentor, Ohio
Posts: 12,156
I know the 80's GMs (like my 84 Camaro), you could jumper a couple pins and force the car to flash the CEL in patterns to expose the code.
Pre-ODBII did not have power at the connector like ODBII does (it sucked, you had to plug the scan tool to the connector and a cig lighter and if the lighter was dead, some gave you alligator clips to go to the car's battery). ODBII is super nice giving power, ground and data.
I am guessing your connector has a data pin and a ground or it's two pins required for data.
Pre-ODBII did not have power at the connector like ODBII does (it sucked, you had to plug the scan tool to the connector and a cig lighter and if the lighter was dead, some gave you alligator clips to go to the car's battery). ODBII is super nice giving power, ground and data.
I am guessing your connector has a data pin and a ground or it's two pins required for data.
#3
I am not sure how they should be. I had a 95 MCZ34 and I had one that was 12 pin and only A an M were present. One of my friends had a 95 that had 3 pins. With his I was able to Jump A and B pins to get the dash to flash the codes. With mine I was told by Chevy when I took it in for service. My car was an Older 95 system and my friends was built after mine and had the updated port.
I am going to guess that your car is also with an older OBD port and only offers Ground at A and the Serial Port at M.
I am going to guess that your car is also with an older OBD port and only offers Ground at A and the Serial Port at M.
#4
that sounds logical as the Brickyard MC was introduced in 94 to coincide with the 1st Brickyard 400 for Nascar.
If you have the local GM dealer check your Vin# they would be able to tell you when the car was made.
If you have the local GM dealer check your Vin# they would be able to tell you when the car was made.
#5
Hmmm, you don't suppose a Chevy dealership would be the only place that could read the airbag (and any other) trouble codes on this car; sure, it's a viable option (there's one just a few miles up the road), but I guess if no other place could, they would.